Technical data

5-48
Operating Concepts
Limit Line Operation
For each segment, the table lists the segment number, the starting stimulus value, upper limit, lower limit,
and limit type. The ending stimulus value is the start value of the next segment, or a segment can be
terminated with a single point segment. You can enter limit values as upper and lower limits or delta limits
and middle value. As new limit segments are defined, the tabular listing is updated. If limit lines are
switched on, they are shown on the display.
If no limits have been defined, the table of limit values shows the notation EMPTY. Limit segments are added
to the table using the ADD, softkey or edited with the EDIT, softkey, as previously described. The last
segment on the list is followed by the notation END.
Edit Segment Menu
This menu sets the values of the individual limit segments. The segment to be modified, or a default
segment, is selected in the edit limits menu. The stimulus value can be set with the controls in the entry
block or with a marker (the marker is activated automatically when this menu is presented). The limit
values can be defined as upper and lower limits, or delta limits and middle value. Both an upper limit and a
lower limit (or delta limits) must be defined: if only one limit is required for a particular measurement,
force the other out of range (for example +500 dB or
−500 dB).
As new values are entered, the tabular listing of limit values is updated. Segments do not have to be listed
in any particular order: the analyzer sorts them automatically in increasing order of start stimulus value
when the DONE, key in the edit limits menu is pressed. However, the easiest way to enter a set of limits is
to start with the lowest stimulus value and define the segments from left to right of the display, with limit
lines turned on as a visual check. Phase limit values can be specified between +500
° and −500°. Limit
values above +180
° and below −180° are mapped into the range of −180° to +180° to correspond with the
range of phase data values.
Offset Limits Menu
This menu allows the complete limit set to be offset in either stimulus value or amplitude value. This is
useful for changing the limits to correspond with a change in the test setup, or for device specifications that
differ in stimulus or amplitude. It can also be used to move the limit lines away from the data trace
temporarily for visual examination of trace detail.